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Figure 5 | BMC Molecular Biology

Figure 5

From: Checkpoint effects and telomere amplification during DNA re-replication in fission yeast

Figure 5

Comparison of regions amplified during DNA re-replication with active S phase origins. (A) From top to bottom, the panels show (for chromosome 1) the DNA re-replication profiles at 25 hours after thiamine removal of wild-type cells (green) and rad3 Δ cells (red); the replication profile of wild-type cells replicating under normal conditions in the absence of HU; and the replication profile of wild-type cells replicating in the presence of HU. No smoothing of data was performed. The overall efficiencies of origin firing during HU treatment, from the studies by Mickle et al. [31], are plotted as black sticks below the HU-arrested replication profile. The lengths of the sticks represent the levels of efficiency of the origins during the HU treatment. The longer the stick, the more efficiently the origin fired. Note that the measure of overall efficiency employed by Mickle et al. combined efficiency in wild-type cells with efficiencies in checkpoint-mutant cells [31]. For this reason, telomeric origins in chromosomes 1 and 2 show relatively high efficiencies, even though the extents of replication at telomeres were small in wild-type cells. The bottom panel shows the cumulative sum of origin scores in a sliding 100-kb window. Centromeres are indicated by yellow squares. The region spanning 0.8 kb to 1.8 kb along chromosome 1 is highlighted by a light purple box. (B) A closer look at the highlighted amplified region (light purple box in (A)) shows that the pattern of re-replication is clearly different from patterns of replication. (C) The amount of replication under HU stress was compared to the amount of re-replication by plotting relative copy numbers under HU stress for 4 hours [31] against re-replicated to control DNA ratios for strains 25 hours after thiamine removal. Re-replicated to control DNA ratios and relative copy numbers for all probes were plotted for wild-type, cds1 Δ, and rad3 Δ. Trendlines and R-squared values are provided in all graphs. The rad3 Δ strain displayed a slight correlation, lacking in the wild-type and cds1 Δ strains.

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